Quick-change electric sign

ABSTRACT

The message on this electric sign can be quickly changed from one message to another letter-by-letter by removing a conductor bridge bar from the sign lamp circuit block illuminating the lamp forming the first letter and substituting another conductor bridge bar for illuminating the necessary lamps for the new first letter and so on similarly for each letter of each word. Each letter of the alphabet has a different bridge bar according to the lamps required to outline that letter in its lamp circuit block, and a word in the sign is made up of a combination of lamp circuit blocks employing a different bridge bar for each different letter of the word. Each lamp employed for outlining the letters is a special lamp of the type disclosed and claimed in my copending application Ser. No. 730,407 filed May 20, 1968 for Dual Voltage Automatic-Switching Electric Lamp, now U.S. Pat. No. 3,524,100. The filament of this special lamp is initially energized by a starting voltage and automatically shifted over to an operating voltage by a thermostatic switch contained within the lamp bulb and responsive to the heat emitted by the filament. The instant the operating circuit is interrupted, the cooling of the filament causes the thermostatic switch within each lamp to shift back to its starting voltage contact ready to be reenergized by the next closing of the circuit thereof, as by the substitution of another bridge bar. The use of this lamp in the present sign circuit eliminates many relays and controllers required in prior sign circuits. The sign itself contains as many blocks of lamps as are necessary to form the desired message with the maximum number of letters, e.g. a 50-letter message would require 50 blocks of lamps with 50 bridge bars or other selective bulb-group-energizing switches or controllers, spacing between words on the same line being accomplished by energized blocks spaced by unenergized blocks.

' 3,239,894 4/1941 Keen United States Patent Johnny E. Blair Box 3, Van, W. Va. 25206 [2i] Appl. No. 776,941

[22] Filed Nov. 19, I968 [45] Patented July 20, 1971 [72] lnventor [54] QUICK-CHANGE ELECTRIC SIGN UNITED STATES PATENTS Prim l y E min8r-l1alph D. Blakes lee Attorney-Barthel and Bugbee ABSTRACT: The message on this electric sign can be quickly changed from one message to another letter-by-letter by removing a conductor bridge bar from the sign lamp circuit block illuminating the lamp forming the first letter and substituting another conductor bridge bar for illuminating the necessary lamps for the new first letter and so on similarly for each letter of each word. Each letter of the alphabet has a different bridge bar according to the lamps required to outline that letter in its lamp circuit block, and a word in the sign is made up of a combination of lamp circuit blocks employing a different bridge bar for each different letter of the word. Each lamp employed for outlining the letters is a special lamp of the type disclosed and claimed in my copending application Ser. No. 730,407 filed May 20, 1968 for Dual Voltage Automatic- Switching Electric Lamp, now U.S. Pat. No. 3,524,100. The filament of this special lamp is initially energized by a starting voltage and automatically shifted over to an operating voltage by a thennostatic switch contained within the lamp bulb and responsive to the heat emitted by the filament. The instant the operating circuit is interrupted, the cooling of the filament causes the thermostatic switch within each lamp to shift back to its starting voltage contact ready to be reenergized by the next closing of the circuit thereof, as by the substitution of another bridge bar. The use of this lamp in the present sign circuit eliminates many relays and controllers required in prior sign circuits. The sign itself contains as many blocks of lamps as are necessary to form the desired message with the maximum number of letters, e.g. a SO-letter message would require 50 blocks of lamps with 50 bridge bars or other selective bulb-group-energizing switches or controllers, spacing between words on the same line being accomplished by ener-v gized blocks spaced by unenergized blocks.

PATENTED JULZO I97! SHEET 3 UF 3 INVENTOR 5 a a? z 5 5 5 5 m 2 2 2 M 2 m u 5 4 3 5 n 2 2 M 2 R 2 M 5 2 5 I 2 m 2 2 z a U 2 2 I2 I I n u 2 2 2 w 2 D l m. B m 2 m w M m M2 M5 m mm m 2 a 5 R I m w a m 5 I I z 5 A 3 5 B o w m M w I I E2 I 6 m a u 2 I B I m R la O70! IIZ /III 5 N I o. I 5 m H 2 m 8 b 6 w w o 4 a m B 8 6 B 6 8 c I I M 6 Q 8 E 6 5 H 5 6 a m 5 I s e a s 4 9 4 5 4 m 4 5 a a 3 6 3 3 E3 w 2 I 3 3 z 2 2 5 2 2 I u 1! III-III! m 2 3 56789 FIG.5 JOHNNY E. BLAIR BY fiwrlhv ATTORNEYS QUICK-CHANGE ELECTRIC SIGN In the drawings:

FIG. I is a wiring diagram of an electric sign lamp circuit block showing a bridge bar in position, the live contacts of which energize the requisite lamps for forming the capital letter A, with the illuminated lamps indicated by heavy-line circles;

FIG. 2 is a diagrammatic view of a bridge bar arranged to be substituted for the bridge bar in FIG. I to illuminate the lamps necessary to form the capital letter 8;

FIG. 3 is a view similar to FIG. 2 but of a bridge bar arranged to illuminate the lamps necessary for forming the capital letter C;

FIG. 4 is a chart showing the "live" contacts for a complete set of bridge bars for illuminating the lamps necessary for forming all the capital letters of the alphabet;

FIG. 5 is a chart similar to that of FIG. 4 but showing the live" contacts necessary for a complete set of bridge bars for illuminating the lamps for forming all the numerals from 0 to 9 inclusive;

FIG. 6 is a diagrammatic view of one of the special lamps used in the lamp circuit blocks of the sign; and

FIG. 7 is a simplified wiring diagram of an electric sign lamp circuit block similar to FIG. I but employing standard electric lamps rather than the special lamps of FIG. 1.

Referring to the drawings in detail, FIG. I shows an electric lamp circuit block, generally designated 30, containing a network or array 32 of special electric lamps 34 for forming any cardinal numeral or letter of the alphabet. The electric sign for presenting the desired message is made up of the necessary number of circuit blocks 30 according to the maximum number of letters plus numerals, if any, including necessary spaces, which the sign is designed to employ. Such signs are especially suitable for business establishments the message conveyed by the sign is preferably changed frequently. Such a typical establishment of this character is a restaurant where the sign during breakfast hours might read Breakfast now serving" and during the luncheon hours Luncheon now serving" and so forth.

Associated with each circuit block 30 is a lamp-energizing subcircuit selector or bridge bar 36, with selected live contacts. Three such bridge bars 26 are shown for convenience of disclosure and are additionally designated with a specific added letter according to the letter of the alphabet which it forms. Thus, the bridge bar 36 shown at the bottom of FIG. I is designated 36A because it causes the circuit block 30 to form the letter A, the bridge bar shown in FIG. 2 is designated 368 because it forms the letter B and that of FIG. 3 36C because it forms the letter C. Each bridge bar 36 possesses 25 individual movable contacts or plugs corresponding to the 25 lamps 34 in the lamp assemblage 32 and numbered I to 25 inclusive. The positions and contact numbers left blank in FIGS. 1, 2 and 3 for the bridge bars 36A, 36B and 36C are those which are not provided with live movable contacts. Each bridge bar 36 includes a handle 36 of insulating material indicated by the dotted line at the bottom of FIG. 1 and also in FIGS. 2 and 3. The handle 36 provides convenience and safety for the operator but it otherwise does not enter into the electrical operation.

Extending through the handle 38 of each bridge bar 36 is a main conductor 40 having a movable contact 42 which is connectable to a fixed contact 44. The latter is connected to a starting current control line 46 leading through a normally open control switch 48 to a line 50 which in turn is connected to a source of electric starting current (not shown). The bridge bar 36 also has a set 52 of movable contacts or blades projecting from the handle 38 and connected to the main conductor 40 thereof. The individual contacts of the movable contact set 52, numbered from I to 25 inclusive, correspond with the individual numbers I to 25 inclusive of the electric lamps 34 in the network array 32. The individual fixed contacts or sockets of the set 54 thereof are numbered in the same manner as the individual movable contacts but are distinguished by the addition of prime" to each number, namely from 1' to 25'. The movable'contact set 52 registers with and is adapted to detachably engage the fixed contact set 54 with the movable contact 1 engaging the fixed contact 1', the movable contact 2 engaging the fixed contact 2and so forth.

A starting current ground line 56 leads from each lamp 34 to the previously mentioned source of starting current and with the line 50 constitutes a starting current supply circuit 57, as described below. An operating current ground line 58 leads from each lamp 34 to a source of operating current (not shown) and with an operating current control line 59 constitutes an operating current supply circuit 60, as described below.

Each of the fixed contacts I to 23' is connected to one of the special thermostatically switching electric lamps 34 which are of the type disclosed and claimed in my above-identified application Ser. No. 730,407 filed May 20, I968. Briefly described, this lamp 34 includes a conventional metallic base 62 either of the so-called Edison screw-type or the Ediswan bayonet-type or any other suitable type insertable in a conventional socket (not shown) having contacts engaged by corresponding contacts in the base 62, which are numbered directly with reference numerals for purposes of identification. The lamp 34 has a translucent envelope or bulb 64, for example of glass, joined to a reversely directed hollow stem 66 and enclosing a chamber 68 either evacuated or filled with an inert gas, such as nitrogen or argon. Seated in and sealed in the stem 66 are two oppositely bent filaments supports 70 and 72 respectively to which are joined the opposite ends of an electric lamp filament 74 oftungsten or other suitable material.

Also seated and sealed in the central insulated portion 76 of the base 62 and in the hollow stem 66 are the upper and lower fixed pole or contact supports 78 and 80 respectively for the upper and lower fixed poles or contacts 82 and 84 respectively of a thermostatic switch 86. The movable bimetallic switch blade 88 is composed of two strips of dissimilar metals having different coefficients of thermal expansion such that, when heated by the filament 74, the differential expansion thereof causes the switch blade 88 to shift with a snap action from its normal engagement with the upper fixed pole or contact 82 to engagement with the lower fixed pole or contact 84. When the filament 74 is deenergized, the consequent cooling of the switch blade 88 causes it to snap back into engagement with the upper fixed pole or contact 82.

From FIG. 6 it will be seen that the right-hand filament support 72 is connected at its lower end to a lamp base contact 90 which in turn is connected through its socket (not shown) to the starting current ground line 56 and also to the operating current ground line 58. The upper and lower fixed contact supports 78 and 30 are connected respectively to lamp base contacts 92 and 94. The base contact 92 is connected through its socket to the starting current control line 96 which leads through one of the fixed contacts of the set 54 and one of the movable contacts of the set 52 through the handle conductor 40, movable contact 42, fixed contact 44, line 46, switch 48 and line 50 to the source of starting current (not shown). The third and last lamp base contact 94 leads through its socket (not shown) to the operating current control line 59 which is connected through a normally closed operating current control switch 100 to an operating current supply line 102 which in turn leads to the same outside source of operating current (not shown) as the line 58 and which, with the line 58, constitutes the operating current supply circuit 60. The lamp subcircuit, generally designated I04, shown in FIG. 5 is the same for each of the 25 lamps 34 and each subcircuit 104 is distinguished from the remaining subcircuits by the reference numerals l to 25 inclusive assigned to the movable contacts of the bridge bars 36 and the reference numerals I to 25 inclusive assigned to the fixed contacts of the lamp circuit block 30. The energization of each lamp subcircuit I04 will of course depend on whether its particular bridge bar 36 for the selected letter to be illuminated on the sign is plugged in and also whether or not the particular bridge bar 36 has a movable contact of the set 52 which is plugged into the corresponding fixed contact.

In the operation of the invention, let it be assumed that the electric sign is composed of a series of letters (or numerals, if numbers are to be indicated) and that the first letter to be formed is the letter A as indicated in FIG. 1. Let it also be assumed that the sign contains tne number of identical lamp circuit blocks 30 necessary to fon'n the words of the message, the procedure for and operation of each block 30 being identical to those of the others, except for the particular lamps illuminated, according to the letter or numeral being formed.

To form the letter A (FIG. I), the operator selects a bridge bar or other controller 36A having a set 52 of movable contacts or blades necessary to form the desired letter A. In this instance the lamps 34 to be illuminated are indicated by extra heavy circles and those not illuminated by light circles. Thus, the bridge bar 36A for forming the letter A possesses movable contacts or switch blades 1 to 6 inclusive, 8, 11, 13, I6, 18 and 21 to 25 inclusive, all being connected to the main conductor 40 within the handle 38 which in turn in conditioned for subsequent energization by the engagement of the movable contact 42 with the fixed contact 44. The above numbered movable contacts of the set 52 engage the correspondingly primenumbered fixed contacts of the set 54 when the bridge bar 36A is moved into its operative position shown in FIG. I.

To illuminate the sign and thereby form the capital letter A, the operator closes the normally open switch 48, closing the circuit between the lines 50 and 56 connected to the ""766 of starting current and thus energizing the lamps 34 preselected by the above-numbered movable and fixed contacts of the sets 52 and 54. Each lamp is illuminated in the manner shown in FIG. 5 wherein the closing of the normally open switch 48 causes starting current to flow through the line 96, base contact 92, upper contact support 78 and upper contact 82, thermostatic switch blade 88, filament support 70, filament 74, filament support 72, base contact 92 and starting current ground line 56.

Thus energized by starting current, the filament 74 becomes incandescent by its resistance and radiates heat to the thermostatic switch blade 88 which by reason of its bimetallic composition expands unequally on opposite sides thereof so as to bend downward with a snap action from its normal engagement with the upper contact 82 to engagement with the lower contact 84 of the thermostatic switch 86. This action disconnects the filament 74 from the starting current source supplied by the starting current supply lines 50 and 56 and connects the filament 74 with the operating current supply lines 58 and 102. The operating current then flows from the line 102 (FIG. 6) through the normally closed switch 100 and line 59 to the base contact 94 of the lamp 34, thence by way of the lower contact support 80, lower contact 84, thermostatic switch blade 88, left-hand filament support 70, filament 74, righthand filament support 72, base contact 90 and operating current ground line 58 to the operating current source, completing the circuit. The heat emitted by the filament 74 continues to cause the bimetallic switch blade 88 to maintain contact with the lower fixed contact 84 until the operator desires to extinguish the lamps 34 which he does by opening the normally closed switch I00. While FIGS. 1 and 5 show the switches 48 and I for the illumination ofa single letter A, it will be evident that one such pair of switches 48 and I00 will control all of the circuit blocks 30 which make up the sign. The consequent deenergization of the filament 74 by the opening of the normally closed switch 100 causes the switch blade 88 to cool and therefore to bend upward by its differential expansion out of engagement with the lower fixed contact 84 and into reengagement with the upper fixed contact 82, ready for reenergization of the lamp 34 when the switch 48 is again slowed.

If, now, the operator desires to illuminate the capital letter A, for example, he substitutes the bridge bar 368 for the bridge bar 36A in the circuit block 30. From a comparison of the bridge bars 36A and 368 in FIGS. 1 and 2 it will be seen that the bridge bar 365 possesses all of the live" contacts or movable contacts of the bridge bar 36A with the exception of the movable contact 23 thereof, and in addition has added movable contacts I0, 15 and 20. Consequently, the additional lamps 34 illuminated by the additional switch blades 10, 15 and 20 convert the capital letter A formed by the bridge bar 3i i into the capital letter B, the omission of the movable contact 23 causing the extinguishment of the corresponding lamp 34 to indicate the indentation on the right-hand side of the capital letter B.

If on the other hand, the operator wishes to form the capital letter C by illuminating the proper lamps 34 in the circuit block 30, he substitutes the bridge bar 36C for the bridge bars 368 and 36A. By a comparison of the bridge bar 36C with the bridge bar 363 of FIGS. 3 and 2 respectively, it will be seen that the bridge bar 36C omits the movable contacts 8, 13, I8, 22, 23 and 24 and retains the contacts I to 6 inclusive, l0, l1, l5, 16, 20, 21 and 25. Thus, when the normally open switch 48 is closed, the capital letter C will be illuminated in the circuit block 30. The table or chart of FIG. 4 shown for each capital letter of the alphabet the live" movable contacts necessary on the bridge bar or controller for each such letter. The capital letters I and V require the least number of such contacts, each requiring only five contacts. The capital letter B, on the other hand, requires the maximum number of contacts, namely 18 of the 25 possible movable contacts.

While the terms fixed" and movable contacts have been employed for the sets 54 and 52 respectively, in actual practice the sockets and plugs fitting those sockets would conveniently be employed.

The formation of numerals by illuminating selected lamps 34 follows the same principle as in the formation of alphabet letters. Thus, the numeral 1 will be the same as the capital letter I, and the number 0 will be the same as the capital letter 0. FIG. 5 shows the live" contacts on the bridge bars 36 necessary for forming all of the numerals from 0 to 9 inclusive. Numerals composed of two or more digits will, of course, use two lamp circuit block 30, one for each such digit.

From FIG. 1 it will be observed that the switch 48 is inserted in the circuit block 30 for the convenience of the operator and could be omitted because the bridge bar 36 itself acts as a circuit breaker when its blades or plugs 52 are inserted or removed from engagement with their corresponding contacts or sockets 54.

It will further be recalled from the foregoing description of the operation that even ifthe bridge bar 36 is left engaged with the fixed contacts 54 and 44, the circuit through it becomes cleadas soon as the thermostatic switch 88 within each lamp 34 shifts from the upper contact 82 to the lower contact 84 and thus shifts the circuit over to the operating circuit 60. Thus, the bridge bar 36 for each letter or numeral is no longer needed once the operating current circuit becomes energized, until the next change of message on the sign is required to be made.

The modified sign lamp circuit block, genera y designatc; 110, shown in FIG. 7 is a simplification of the "lcuit block 30 using a network 112 of two-contact electric lamps 114 instead of the network 32 of the special three-contact electric lamps 34 used in the lamp circuit block 30 of FIG. 1. In comparing the simplified lamp block circuit 110 of FIG. 7 with the lamp block circuit 30 of FIG. I, it will be observed that the operating circuit 60 with its lines 58 and 59 and switch have been omitted, and that the momentary contact switch 48 has been replaced by a sustained contact switch 116, for example a double-pole single-throw switch. In the simplified circuit block I10, the arrangement of the fixed contacts 54 and movable contacts 52 of the various bridge bars 36 for energizing the subcircuit 118 for each lamp 114 corresponds to those employed for the block circuit 30 of FIG. 1 and shown for the various letters of the alphabet in the chart of FIG. 4 and for the various digits in the chart of FIG. 5.

In the simplified block circuit 110 using standard two-contact electric lamps 114, however, the various bridge bars 36 must be kept constantly engaged with their respective fixed contacts 54 as long as each circuit block 110 is energized to illuminate the particular pattern of lamps 114 necessary to form the chosen letter or numeral, Thus, each of the lamp circuit block 110 required to form the message has to have a bridge bar 36 and this cannot be'removed as long as the sign is in operation with its particular message. Thus if, for example, the letter "B" is repeated in the various words of the message, as many bridge bars 36E as that number of repeated letters would be required in the circuit block 110 of FlG. 7 and kept constantly engaged, whereas only one bridge bar for each letter would be required in the lamp block circuit 30 of FIG. 1 if the separate letters of each work were energized separately.

lclaim:

l. A quick-change electric sign, comprising a multiplicity of fixed electrical contacts disposed in proximity to one another,

a multiplicity of electric lamps disposed in a network arrangement adapted by selective illumination of different combinations of lamps to form luminous outlines of different alphabetical and numerical characters, each lamp having a translucent envelope containing an illuminating element which becomes luminous and heatemitting in response to electrical energization thereof and a thermostatic switch with a starting current pole, an operating current pole and a thermally movable switch member connected to said luminous element andnormally engaging said starting current pole but responsive to the electrical energization of said element antic-consequent heat-emission therefrom to shift said member out of engagement with said starting current pole and into engagement with said operating current pole,

a starting current supply circuit adapted to be connected to a source of starting current electricity,

an operating current supply circuit adapted to be connected to a source of operating current electricity,

a multiplicity of lamp energization subcircuits each including one of said lamps and each connected to said operating current supply circuit and to one of said fixed contacts,

and subcircuit selection means connected to said starting current supply circuit and movable into engagement with certain of said fixed contacts for energizing the subcircuits connected thereto and illuminating the lamps thereof in a predetermined letter or numeral pattern.

2;, A quick-change electric sign, according to claim I, wherein said fixed contacts are disposed side-by-side in laterally spaced relationship, and

wherein said subcircuit selection means includes a subcircuit selector having a main conductor connected to said other current supply circuit and having movable subcircuit selecting contacts connected to said main conductor and movable into engagement with certain of said fixed contacts.

3. A quick-change electric sign, according to claim 2, wherein said selector comprises a bridge structure containing said main conductor and holding said movable contacts transverse thereto.

4. A quick-change electric sign, according to claim 1 wherein said starting current supply circuit includes a normally open starting switch adapted when closed to supply said starting current to said subcircuit selection means.

5. A quick-change electric sign, according to claim 1, wherein said operating current supply circuit includes a normally closed switch adapted when opened to terminate flow of operating current through said operating current supply circuit.

6. A quick-change electric sign, according to claim 1, wherein said network arrangement disposed said lamps in a rectangular checkerboard pattern.

7. A quick-change electric sign, according to claim I, where v said subcircuit selection means includes a plurality of subcir-' cuit selectors each adapted to energize one of a collection of subcircuits to illuminate said lamps in different alphabetical and numerical patterns.

8. A quick-change electric sign, according to claim 1, wherein said fixed contacts comprise sockets arranged in close proximity to one another, and

wherein said subcircuit selection means includes a holder having plugs alignable with said sockets and engagement therewith, said plugs being positioned to engage certain of said sockets energizing their respective lamps in a selected alphabetical or numerical pattern.

9. A quick-change electric sign, according to claim 8, wherein said holder comprises a bridge structure containing a main conductor electrically interconnecting said plugs,

wherein an additional socket is provided and connected to said starting current circuit, and

wherein an additional plug is connected to said main conductor and is engageable with said additional socket.

10. A quick-change electric sign, comprising a multiplicity of fixed electrical contacts disposed in proximity to one another,

a multiplicity of electric lamps disposed in a network arrangement adapted by selective illumination of different combinations of lamps to form luminous outlines of different alphabetical and numerical characters, each lamp having a translucent envelope containing an illuminating element which becomes luminous in response to electrical energization thereof and which is connected to a pair of contacts disposed externally of said envelope, 7

a current supply circuit adapted to be connected to a source of current electricity,

a multiplicity of lamp energization subcircuits each including one of said lamps and each connected to said current supply circuit and to one of said fixed contacts,

and subcircuit selection means connected to said current supply circuit and movable into engagement withcertain of said fixed contacts for energizing the subcircuits connected thereto and illuminating the lamps thereof in a predetermined letter or numeral pattern, said fixed contacts being disposed side-by-side in laterally spaced relationship, and said subcircuit selection means including a subcircuit selector having a main conductor connected to said current supply circuit and having movable subcircuit selecting contacts connected to said main conductor and movable into engagement with certain of said fixed contacts. 

1. A quick-change electric sign, comprising a multiplicity of fixed electrical contacts disposed in proximity to one another, a multiplicity of electric lamps disposed in a network arrangement adapted by selective illumination of different combinations of lamps to form luminous outlines of different alphabetical and numerical characters, each lamp having a translucent envelope containing an illuminating element which becomes luminous and heat-emitting in response to electrical energization thereof and a thermostatic switch with a starting current pole, an operating current pole and a thermally movable switch member connected to said luminous element and normally engaging said starting current pole but responsive to the electrical energization of said element and consequent heat-emission therefrom to shift said member out of engagement with said starting current pole and into engagement with said operating current pole, a starting current supply circuit adapted to be connected to a source of starting current electricity, an operating current supply circuit adapted to be connected to a source of operating current electricity, a multiplicity of lamp energization subcircuits each including one of said lamps and each connected to said operating current supply circuit and to one of said fixed contacts, and subcircuit selection means connected to said starting current supply circuit and movable into engagement with certain of said fixed contacts for energizing the subcircuits connected thereto and illuminating the lamps thereof in a predetermined letter or numeral pattern.
 2. A quick-change electric sign, according to claim 1, wherein said fixed contacts are disposed side-by-side in laterally spaced relationship, and wherein said subcircuit selection means includes a subcircuit selector having a main conductor connected to said other current supply circuit and having movable subcircuit selecting contacts connected to said main conductor and movable into engagement with certain of said fixed contacts.
 3. A quick-change electric sign, according to claim 2, wherein said selector comprises a bridge structure containing said main conductor and holding said movable contacts transverse thereto.
 4. A quick-change electric sign, according to claim 1 wherein said starting current supply circuit includes a normally open starting switch adapted when closed to supply said starting current to said subcircuit selection means.
 5. A quick-change electric sign, according to claim 1, wherein said operating current supply circuit includes a normally closed switch adapted when opened to terminate flow of operating current through said operating current supply circuit.
 6. A quick-change electric sign, according to claim 1, wherein said network arrangement disposed said lamps in a rectangular checkerboard pattern.
 7. A quick-change electric sign, according to claim 1, where said subcircuit selection means includes a plurality of subcircuit selectors each adapted to energize one of a collection of subcircuits to illuminate said lamps in different alphabetical and numerical patterns.
 8. A quick-change electric sign, according to claim 1, wherein said fixed contacts comprise sockets arranged in close proximity to one another, and wherein said subcircuit selection means includes a holder having plugs alignable with said sockets and engagement therewith, said plugs being positioned to engage certain of said sockets energizing their respective lamps in a selected alphabetical or numerical pattern.
 9. A quick-change elecTric sign, according to claim 8, wherein said holder comprises a bridge structure containing a main conductor electrically interconnecting said plugs, wherein an additional socket is provided and connected to said starting current circuit, and wherein an additional plug is connected to said main conductor and is engageable with said additional socket.
 10. A quick-change electric sign, comprising a multiplicity of fixed electrical contacts disposed in proximity to one another, a multiplicity of electric lamps disposed in a network arrangement adapted by selective illumination of different combinations of lamps to form luminous outlines of different alphabetical and numerical characters, each lamp having a translucent envelope containing an illuminating element which becomes luminous in response to electrical energization thereof and which is connected to a pair of contacts disposed externally of said envelope, a current supply circuit adapted to be connected to a source of current electricity, a multiplicity of lamp energization subcircuits each including one of said lamps and each connected to said current supply circuit and to one of said fixed contacts, and subcircuit selection means connected to said current supply circuit and movable into engagement with certain of said fixed contacts for energizing the subcircuits connected thereto and illuminating the lamps thereof in a predetermined letter or numeral pattern, said fixed contacts being disposed side-by-side in laterally spaced relationship, and said subcircuit selection means including a subcircuit selector having a main conductor connected to said current supply circuit and having movable subcircuit selecting contacts connected to said main conductor and movable into engagement with certain of said fixed contacts. 